General Approach to Trauma Patients

Published on 07/03/2015 by admin

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Last modified 07/03/2015

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Chapter 2 General Approach to Trauma Patients

4 What are the most important causes of hypotension in the trauma patient?

Hemorrhagic shock—bleeding—is the most common cause of hypotension in the trauma patient. A vigorous search for bleeding is the key to the initial evaluation of any trauma patient with hypotension. Even a single episode of hypotension (systolic blood pressure [SBP] < 100-110 mm Hg) should be considered a potential harbinger of serious injury requiring interventional hemorrhage control. Methods for rapid localization of hemorrhage are discussed in Question 5.

Obstructive shock is that caused by tension pneumothorax or pericardial tamponade. Pericardial tamponade is usually diagnosed with the help of ultrasound examination. Tension pneumothorax is usually diagnosed clinically by mechanism and physical examination. Occasionally ultrasound or chest radiographic examination may be of assistance, but one should never wait to obtain these studies when the diagnosis is suspected.

Spinal shock is a form of neurogenic shock that occurs because of the loss of sympathetic tone and peripheral vasodilation that occurs with high (typically T4 level or above) spinal cord injuries. It should be suspected when the patient has had a compatible mechanism of injury, the hypotension is accompanied by bradycardia, and results of the neurologic examination are consistent (lower extremity paralysis, loss of rectal tone, and a compatible sensory level).

Cardiogenic shock may result from traumatic cardiac contusion or occasionally from preexisting cardiac pathologic condition (coronary disease, valvular lesions, congestive heart failure) in patients with other, noncardiac trauma.

5 How can I rapidly identify the source of bleeding in hemorrhagic shock?

Delayed control of bleeding ranks with airway compromise as a major preventable cause of trauma death. To be controlled, the source of bleeding must be rapidly identified. Hypotension due to hemorrhage typically does not occur until a trauma patient has lost 30% to 40% of his or her blood volume. This quantity of blood can be lost only into a limited number of places. The most important of these places are, externally, the chest, the abdomen, the retroperitoneum, and occasionally the thighs. Patients with hypotension should not undergo prolonged imaging such as computed tomography (CT), and all these potential areas of bleeding must usually be evaluated in the emergency department in a matter of minutes. This is possible with reasonable sensitivity for major hemorrhage with use of a combination of physical examination, ultrasound scan, and plain radiography, all modalities that are widely and quickly available.

Physical examination is the most important tool for identifying external sources of bleeding. External bleeding is often missed or underappreciated when it is due to scalp wounds (which can result in significant blood loss); wounds in the back or axillae, which may be missed by a cursory examination; or mangled extremities, which may be diffusely oozing.

Physical examination and chest radiographic examination are the keys to identifying thoracic bleeding. Both can be done quickly. Ultrasound may be a useful adjunct (see extended focused abdominal sonography for trauma [E-FAST] later). If reasonable suspicion exists for intrathoracic bleeding, tube thoracostomy may be both diagnostic and therapeutic.

The abdomen is usually evaluated by FAST. If it cannot be performed, or is technically limited, diagnostic peritoneal aspiration or lavage is an alternative.

The retroperitoneum cannot be directly evaluated without CT, but most hemodynamically significant retroperitoneal bleeding is the result of pelvic fractures, which can be detected on a plain radiograph of the pelvis. Although retroperitoneal bleeding due to pelvic fractures generally correlates with the severity of the fracture, even relatively minor fractures may occasionally produce major hemorrhage. Similarly, femur fractures, especially if bilateral, suggest the possibility of significant hemorrhage into the thighs.